In-text Questions (Page 133)<\/span><\/p>\nQuestion 1.
\nHow does binary fission differ from multiple fission?
\nAnswer:
\nBinary fission : This method of reproduction occurs in favourable conditions like enough food, water, temperature, etc. In this process of asexual reproduction, the nuclear division takes place for example Amoeba, Paramecium, Euglena is bacteria, blue green algae in multi-cellular animals like planaria.<\/p>\n
Multiple fission: Many daughter individuals are formed from single parent is called multiple fission. This method of reproduction occurs in unfavourable conditions. The unicellular organism develops a protective covering the cyst over the cell. On return of farourable conditions the cyst breaks and daughter cells are liberated for e.g. Plasmodium.
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Question 2.
\nHow will an organism be benefited if it reproduces through spores?
\nAnswer:
\nIt is common method of reproduction in some bacteria and fungi Rhizopus, Mucor. During spore formation a structure called sporangium develops from the fungal hyphae. The nucleus divides several times within the sporangium and each nucleus with a small amount of cytoplasm develop into a spore. The spores are released; on falling on the suitable substratum they germinate to form new hyphae,
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Question 3.
\nCan you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?
\nAnswer:
\nMode of reproduction that depend on the involvement of two individuals before a new generation can be created. Bulls alone cannot produce new calves nor can hens alone produce new Chicks. In such cases both sexes, males and females are needed to produce new generations.<\/p>\n
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Question 4.
\nWhy is vegetative propagation practised for growing some types of plants?
\nAnswer:
\nThis type of propagation also makes possible that have lost the capacity to produce seeds. Another advantage of vegetative propagation is that all plants produced are genetically similar enough to the parent plant to have all its charateristics. This property of vegetative propagation is used in methods such as layering or grafting to grow many plants like sugar can, roses, grapes for agricultural purposes, for e.g. Banana, Orange, Rose, Jamine, etc.<\/p>\n
Question 5.
\nWhy is DNA copying an essential part of the process of reproduction?
\nAnswer:
\nThe creation of two cells from one involves copying of the DNA as well as of the cellular apparatus. The DNA copying mechanism, as we have noted cannot be absolutely accurate; and the resultant errors are a source of variations is populations of organisms. Every individual organism cannot be protected by variations, but in population.<\/p>\n
In-text Questions (Page 140)<\/span><\/p>\nQuestion 1.
\nHow is the process of pollination different from Fertilization?
\nAnswer:
\nPollination: It is the transfer of pollen grains from the anther of a flower to the stigma.
\nFertilization: The process of nuclear fusion of the make and one egg nucleus is termed as fertilization.<\/p>\n
Question 2.
\nWhat is the role of seminal vesicles and the prostate gland?
\nAnswer:<\/p>\n